C9 Agricultural Engine for Challenger Tractors Caterpillar

Use this procedure to troubleshoot the electrical system if a problem is suspected with the injectors or if any one of the diagnostic codes in Table 1 is active or easily repeated.

Perform this procedure under conditions that are identical to the conditions that exist when the problem occurs. Typically, problems with the injector solenoid occur when the engine is warmed up and/or when the engine is under vibration (heavy loads).

These engines have Hydraulic Electronic Unit Injectors (HEUI) that are hydraulically actuated and electronically controlled. The ECM sends a 105 volt pulse to each injector solenoid. The pulse is sent at the proper time and at the correct duration for a given engine load and speed. The solenoid is mounted on top of the fuel injector body.

If an open is detected in the solenoid circuit, a diagnostic code is generated. The ECM continues to try to fire the injector. If a short is detected, a diagnostic code is generated. The ECM will disable the solenoid circuit. The ECM will periodically try to fire the injector. If the short circuit remains, this sequence of events will be repeated until the problem is corrected.

When an injector is replaced, program the new injector code into the ECM. If the ECM is replaced, all six injector codes must be programmed into the new ECM. Refer to Troubleshooting, "Injector Trim File - Install" for more information.

The Caterpillar Electronic Technician (ET) includes the following tests that aid in troubleshooting the injector solenoids:

"Cylinder Cutout Test"

All active diagnostic codes must be repaired before running the "Cylinder Cutout Test". Use the "Cylinder Cutout Test" to diagnose a malfunctioning injector while the engine is running. When a good injector is cut out, the "Fuel Position" should change. The change in the fuel position is caused by the other injectors that are compensating for the cut out injector. If a malfunctioning injector is cut out, the "Fuel Position" will not change. The "Cylinder Cutout Test" is used to isolate the malfunctioning injector in order to avoid replacement of good injectors.

"Injector Solenoid Test"

Use the "Injector Solenoid Test" to aid in diagnosing an open circuit or a short circuit while the engine is not running. The "Injector Solenoid Test" briefly activates each solenoid. A good solenoid will create an audible click when the solenoid is activated. Cat ET will indicate the status of the solenoid as "OK", "Open", or "Short".

Note: Refer to Illustration 1. Two injector solenoids share a common supply wire. For this reason, an open circuit or a short circuit in a supply wire could cause diagnostic codes for two injector solenoids.

Illustration 1	g01347998
Schematic for the injector solenoids

Test Step 1. Inspect the Electrical Connectors and the Wiring

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Electrical shock hazard. The electronic unit injector system uses 90-120 volts.

1. Remove the electrical power from the ECM.

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Illustration 2	g01339063
Left side engine view (typical example) (1) Valve cover connector for the injector solenoids (2) J2/P2 ECM connector

2. Thoroughly inspect connectors (1) and (2). Refer to Troubleshooting, "Electrical Connectors - Inspect".

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Illustration 3	g01339367
Terminal locations at the P2 ECM connector (P2-99) Injector 5 & 6 supply (P2-104) Injector 1 & 2 supply (P2-105) Injector 6 return (P2-106) Injector 3 return (P2-107) Injector 5 return (P2-108) Injector 4 return (P2-115) Injector 3 & 4 supply (P2-116) Injector 1 return (P2-118) Injector 2 return

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Illustration 4	g01339368
J300 terminals that are associated with the injector solenoids (Terminal 1) Injector 1 supply (Terminal 2) Injector 2 supply (Terminal 3) Injector 3 supply (Terminal 4) Injector 4 supply (Terminal 5) Injector 5 supply (Terminal 6) Injector 6 supply (Terminal 13) Injector 6 return (Terminal 14) Injector 5 return (Terminal 15) Injector 4 return (Terminal 16) Injector 3 return (Terminal 17) Injector 2 return (Terminal 18) Injector 1 return

3. Perform a 45 N (10 lb) pull test on each of the wires in the ECM connector and each of the wires that are associated with injector solenoids.

4. Check the allen head screw on each ECM connector for the proper torque. Refer to Troubleshooting, "Electrical Connectors - Inspect".

5. Check the harness and wiring for abrasions and for pinch points from the injectors to the ECM.

Expected Result:

All connectors, pins, and sockets are completely coupled and/or inserted. The harness and wiring are free of corrosion, of abrasion, and of pinch points.

Results:

• OK - The connectors and the wiring appear to be OK. Proceed to Test Step 2.

• Not OK - There is a problem with the connectors and/or wiring.

  Repair: Repair the connectors or wiring and/or replace the connectors or wiring. Ensure that all of the seals are properly in place and ensure that the connectors are completely coupled. Verify that the repair eliminates the problem.

  STOP

Test Step 2. Check for Logged Diagnostic Codes for the Injector Solenoids

1. Connect Cat ET to the data link connector. Refer to Troubleshooting, "Electronic Service Tools".

2. Restore the electrical power to the ECM.

3. Check for logged diagnostic codes for the injector solenoids on Cat ET.

Expected Result:

There are no logged diagnostic codes for the injector solenoids.

Results:

• OK - No diagnostic codes have been logged. The injector solenoids are operating correctly. There may be a mechanical problem with the injector's fuel delivery. Proceed to Test Step 3.

• Not OK - One or more diagnostic codes have been logged. There may be an electrical problem in the circuit for the injector. Proceed to Test Step 4.

Test Step 3. Perform the "Cylinder Cutout Test"

1. Start the engine.

2. Allow the engine to warm up to normal operating temperature (approximately 77 °C (171 °F)).

3. After the engine is warmed to operating temperature, access the "Cylinder Cutout Test" by accessing the following display screens in order:
   • "Diagnostics"

   • "Diagnostic Tests"

   • "Cylinder Cutout Test"

4. Shut off all parasitic loads such as the air conditioning and the air compressors which could affect the results of the test.

5. Select the start button at the bottom of the screen for the cylinder cutout test on Cat ET.

6. Follow the instructions that are provided in the cylinder cutout test. The cylinder cutout tests are interactive so the procedure is guided to the finish. The cylinder cutout test will set the correct engine speed for the application.

Expected Result:

The variation of the fuel rate for all cylinders is within specifications.

Results:

• OK - The variation of the fuel rate for all cylinders is within specifications.

  Repair: If the engine is misfiring or if the engine has low power, refer to Troubleshooting, "Engine Misfires, Runs Rough or Is Unstable" and Troubleshooting, "Power Is Intermittently Low or Power Cutout Is Intermittent".

  If a diagnostic code results from running the "Cylinder Cutout Test", proceed to Test Step 4.

• Not OK - The cylinder cutout test indicates that at least one of the injectors is not operating correctly. Proceed to Test Step 4.

Test Step 4. Perform the "Injector Solenoid Test"

1. Start the engine.

2. Allow the engine to warm up to normal operating temperature (approximately 77 °C (171 °F)).

3. Stop the engine.

4. Restore the electrical power to the ECM.

5. Access the "Injector Solenoid Test" by accessing the following display screens in order:
   • "Diagnostics"

   • "Diagnostic Tests"

   • "Injector Solenoid Test"

6. Activate the "Injector Solenoid Test".

7. As each solenoid is energized by the ECM an audible click can be heard at the valve cover. Ensure the activation of each solenoid by comparing the location of the click with the progress that is displayed on Cat ET.

8. Perform the injector solenoid test at least two times.

Expected Result:

All cylinders indicate "OK" on Cat ET.

Results:

• OK - There is not an electronic problem with the injectors at this time.

  Repair: Verify that the engine valve lash for that injector is set correctly. Rerun the "Cylinder Cutout Test". If the problem is still present, replace the injector. Change the injector trim file in the ECM. Refer to Troubleshooting, "Injector Trim File - Install".If the codes continue to be logged, refer to Troubleshooting, "Electrical Connectors - Inspect".If the engine is misfiring or if the engine has low power, refer to Troubleshooting, "Engine Misfires, Runs Rough or Is Unstable" or refer to Troubleshooting, "Power Is Intermittently Low or Power Cutout Is Intermittent".

  STOP

• Not OK - "Open" - Note the cylinder that indicates "Open". Proceed to Test Step 5.

• Not OK - "Short" - Note the cylinder that indicates "Short". Proceed to Test Step 6.

Test Step 5. Check the Harness between the ECM and the Valve Cover Base for an Open Circuit

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Electrical shock hazard. The electronic unit injector system uses 90-120 volts.

1. Remove the electrical power from the ECM.

2. Disconnect the valve cover connectors that are for the injector solenoids at the valve cover base.

3. Restore the electrical power to the ECM.

4. Fabricate a jumper wire that will be long enough to create a short circuit across the valve cover connector. Crimp connector pins on both ends of the jumper wire.

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Illustration 5	g01180674
Terminal locations at the valve cover connector for the injector solenoids (left side engine view) (Terminal 1) Injector 1 supply (Terminal 2) Injector 2 supply (Terminal 3) Injector 3 supply (Terminal 4) Injector 4 supply (Terminal 5) Injector 5 supply (Terminal 6) Injector 6 supply (Terminal 13) Injector 6 return (Terminal 14) Injector 5 return (Terminal 15) Injector 4 return (Terminal 16) Injector 3 return (Terminal 17) Injector 2 return (Terminal 18) Injector 1 return

5. Insert one end of the jumper wire into the terminal location at the valve cover connector for the suspect injector's supply wire. Insert the other end of the jumper wire into the terminal location for the suspect injector's return wire. This will effectively replace the injector solenoid with a short circuit.

6. Perform the "Injector Solenoid Test" at least two times.

7. Repeat this test for each suspect solenoid circuit. Stop the "Injector Solenoid Test" before handling the jumper wire. Restore the wiring to the original configuration.

Expected Result:

Cat ET displays "Short" for each of the circuits that were jumpered.

Results:

• OK - Cat ET displays "Short" for each circuit that was jumpered. The harness between the ECM and the valve cover connector does not have an open circuit. Proceed to Test Step 7.

• Not OK - Cat ET displays "Open" for the cylinder with the jumper wire. There is a problem in the wiring between the ECM and the valve cover connector. There may be a problem with the ECM. Proceed to Test Step 8.

Test Step 6. Check the Harness between the ECM and the Valve Cover Base for a Short Circuit

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Electrical shock hazard. The electronic unit injector system uses 90-120 volts.

1. Remove the electrical power from the ECM.

2. Disconnect the valve cover connector that is for the injector solenoids.

3. Restore the electrical power to the ECM.

4. Perform the "Injector Solenoid Test" at least two times.

Expected Result:

All of the cylinders indicate "Open" on Cat ET.

Results:

• OK - All cylinders indicate "Open" on Cat ET. Proceed to Test Step 7.

• Not OK - One or more cylinders indicate "Short" on Cat ET. Note the cylinders that indicate "Short". Proceed to Test Step 8.

Test Step 7. Check the Injector Harness Under the Valve Cover for an Open Circuit or a Short Circuit

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Electrical shock hazard. The electronic unit injector system uses 90-120 volts.

1. Remove the electrical power from the ECM.

2. Remove the valve cover in order to gain access to the suspect injector.

3. Disconnect the harness connector from the suspect injector.

4. Thoroughly clean the terminals on the injector solenoid and on the harness connector.

5. Fabricate a jumper wire that is long enough to create a short circuit across the connector at the injector connector. Crimp connector sockets to each end of the jumper wire.

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Illustration 6	g01180694
Connector Terminals for the solenoid connector

6. Install the jumper wire across the connector terminals for the suspect injector. This will effectively replace the injector solenoid with a short circuit.

7. Restore the electrical power to the ECM.

8. Perform the "Injector Solenoid Test" at least two times.

   Note: The injector solenoid that shares the supply wire of the injector that is short circuited may indicate a false test result. Disregard this test result.

9. Remove the electrical power from the ECM.

10. Remove the jumper wire from the injector connector. This will effectively replace the injector solenoid with an open circuit.

11. Restore the electrical power to the ECM.

12. Perform the "Injector Solenoid Test" at least two times.

13. Remove the electrical power from the ECM.

Expected Result:

Cat ET displays "Short" for the cylinder with the jumper wire and "Open" when the jumper wire is removed.

Results:

• OK - Cat ET correctly displays the correct status during the test. The harness wiring is OK.

  Repair: Use a multimeter to check the resistance of the suspect injector solenoid.The correct resistance of each injector solenoid is 1.06 ± 0.05 Ohms.If the resistance of the solenoid is not within specifications replace the faulty injector. Verify that the problem is resolved.If the resistance of the solenoid is within specifications, there may be an intermittent electrical problem in the harness or in a connector. If an intermittent problem is suspected, refer to Troubleshooting, "Electrical Connectors - Inspect" for information that is related to troubleshooting intermittent electrical problems.

  STOP

• Not OK - Cat ET did not display the correct status during the test. There is a problem with the injector harness under the valve cover. There may be a problem with a connector.

  Repair: Repair the wiring and/or the connector, when possible. Replace parts, if necessary. Verify that the problem is resolved.

  STOP

Test Step 8. Check the ECM for Proper Operation

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Electrical shock hazard. The electronic unit injector system uses 90-120 volts.

1. Remove the electrical power from the ECM.

2. Fabricate a jumper that is long enough to reach from the P2 ECM connector to the engine ground stud. Crimp a socket terminal to one end of the jumper wire.

3. Disconnect the P2 connector.

4. Remove the supply wire for the suspect injector from the ECM connector. Install the jumper wire into the socket.

5. Connect the J2/P2 ECM connector.

6. Verify that the ECM will detect an open circuit for the suspect injector:

   1. Ensure that the jumper wire is not in contact with any ground source or another circuit. Do not touch the jumper wire during the test. A strong electrical shock hazard is present at the jumper wire while the test is running.

   2. Restore the electrical power to the ECM.

   3. Perform the "Injector Solenoid Test" at least two times.

   4. Remove the electrical power from the ECM.

      For a circuit that is in good repair, Cat ET will display "Open" for the two injectors that share the supply wire.

7. Verify that the ECM detects a short circuit for the suspect injector:

   1. Connect the jumper wire to the engine ground stud. Do not touch the jumper wire during the test. A strong electrical shock hazard is present at the jumper wire while the test is running.

   2. Restore the electrical power to the ECM.

   3. Perform the "Injector Solenoid Test" at least two times.

   4. Remove electrical power from the engine ECM.

      For a circuit that is in good repair, Cat ET will display "Short" for the two injectors that share the supply wire.

Expected Result:

Cat ET displays the correct status for each test circuit.

Results:

• OK - The ECM detects the correct status of the circuit.

  Repair: There is an open circuit or a short circuit in the engine harness. There may be a problem with a connector. Inspect the connectors for moisture and for corrosion. Repair the wiring and/or the connector, when possible. Replace parts, if necessary. Clear all diagnostic codes after you complete this test step.Verify that the problem is resolved.

  STOP

• Not OK - The ECM does not detect the correct status of the circuit.

  Repair: There is a problem with the ECM. Perform the following procedure:

  1. Temporarily connect a test ECM.

     Refer to Troubleshooting, "ECM - Replace".

  2. Recheck the circuit in order to ensure that the original problem has been resolved.

     If the problem is resolved with the test ECM, install the suspect ECM. If the problem returns with the suspect ECM, replace the ECM. Verify that the problem is resolved.

     If the problem is not resolved with the test ECM, install the original ECM. There is a problem in the wiring.

  STOP